Labels are used throughout our society. Stores place labels on goods to be sold indicating price and/or identifying the associated goods by a stock number. Uniform product codes (UPC) are frequently placed on labels or directly on goods to identify the goods. Transferring price labels from one item to another is a constant problem faced by store owners, especially in retail areas where customers may switch labels to pay a lower price for the goods.
Label integrity is also vital in the pharmaceutical industry. Switched labels or mismarked product can cause devastating or fatal results. There is also a trend to permanently mark automotive parts in order to control the use of stolen parts in auto repair work and reduce auto theft. Other industries and products also need labels which maintain label integrity to provide permanent marking and prevent label switching.
Counterfeit products which display a trademark belonging to an authentic manufacturer have infiltrated the marketplace of various industries, including the automobile industry. Manufacturers desire tamper proof packaging, labels, or other indicia of authentication which cannot be readily and cheaply copied by a counterfeiter.
Numerous label designs have attempted to create tamper proof labels which provide an indication of authentication yet is versatile in usage, allowing the label to be selectively affixed to goods, and allowing the label to be written upon.
U.S. Pat. No. 4,268,983 issued to Cook describes a label which has a heat softenable film attached to a support sheet. Both the support sheet and the heat softenable film have a lower adhesive layer located between the product and the label. When the label is removed, the heat softenable sheet is supposed to tear, separating from the support sheet. The top of the heat softenable film may be imprinted with a latent retro-reflective image. Cook requires a heat softenable layer which must be heated or melted to achieve the necessary configuration. The retro-reflective image is applied to specific selected areas and requires at least two different layers, at least one of which is reflective which causes the image and background areas to have different reflective efficiencies. Applying the retro-reflective image is difficult and expensive. Removing the label may also remove the retro-reflective layer preventing authentication if the product is returned.
U.S. Pat. No. 5,042,842 issued to Green employs a multi-layer label consisting of a lower sheet of safety paper and an upper sheet. The lower sheet of safety paper is attached by a permanent adhesive to a product. The upper sheet is attached by a patterned adhesive layer to the lower safety paper layer. Graphics and price information are printed on the top of the upper sheet. Indicia of authentication are printed on the bottom surface of the upper sheet. Authentication requires that the upper portion of the label including the upper sheet be separated from the lower safety paper sheet. Once separated, the layers cannot be rejoined to reconstitute the label. In addition, removal of the top portion is required in order to tell if an additional label has been placed over the top of the upper portion of the label. If the product is subsequently returned, only the lower layer of safety paper will be present on the product. No indicia of authentication is available to authenticate the product at that point.
U.S. Pat. No. 4,721,638 issued to Matsuguchi employs a similar multiple-layer configuration. A top layer is employed which is made of paper. A middle layer consisting of an aggressive adhesive layer is placed between the top paper layer and a bottom paper layer. Printing is applied to the top surface of the top layer, and to the bottom surface of the bottom layer. A bottom layer of adhesive is located in between the bottom of the bottom layer and the product to which the label is affixed. This adhesive layer is weaker than the aggressive middle adhesive layer located between the top layer and the bottom layer of paper. This type of label also requires removal of the label to authenticate the label by viewing the printing located on the bottom of the bottom layer, if it is visible through the lower adhesive layer, or a portion thereof that remains attached to the bottom layer of the label. If the product is returned, no part of the label will be present on the product to authenticate the product. This label may be moved from one product to another without destroying or deforming the label.
U.S. Pat. No. 4,746,556 issued to Matsuguchi describes a label which is also formed of multiple layers. The label consists of a top and bottom layer. Once adhered to a product, any attempt to remove the label will result in the removal of the top layer and a patterned portion of the bottom layer which is characterized as breakable. Portions of the bottom layer will be adhered to the top layer and portions of the bottom layer will remain adhered to the product. Several adhesives of differing strengths are applied in a patterned configuration between the top and bottom layers which causes the bottom layer to break in a predetermined pattern conforming to the pattern of the adhesives applied.
U.S. Pat. No. 4,608,288 issued to Spindler describes a label formed using an outer layer of material which is easily breakable or irreversibly stretchable under tension which is adhesively bonded on top of an intermediate layer. The outer layer of material extends beyond the intermediate layer. The intermediate layer may contain images which authenticate the label. Once the outer layer is removed, the authentication layer is exposed, making further authentication upon return of a product difficult. One version of this label is designed with light refracting properties allowing detection of mechanical stress which has been applied to the label. This version may also become deformed by resting weight on the label, such as by stacking products, and is especially vulnerable when used in automotive applications.